i) Field of the Invention
The present invention relates to novel siloxane derivatives having surface active action useful as an emulsifier, a method for producing the novel siloxane derivatives, and agents including a novel siloxane derivative such as cosmetic preparations, emulsifying dermatotherapeutic external agents making use thereof and the like.
ii) Description of the Background Art
Conventionally, silicone compounds having surface active action are divided into four groups such as compounds having an anionic hydrophilic group, compounds having a cationic hydrophilic group, compounds having a betaine hydrophilic group and compounds having a nonionic hydrophilic group according to kinds of denatured hydrophilic groups.
As to the compounds having a nonionic hydrophilic group, polyoxyalkylene denatured silicone surfactants having a polyoxyalkylene group as a hydrophilic group are known. However, these are inferior in emulsifying stability, and, when it is used as an emulsifier such as cosmetic preparations or the like, in order to obtain sufficient emulsifying stability, a thickener or thickeners such as silica, clay mineral and the like must be further added to.
On the other hand, a polyalcoholic hydroxyl group as the nonionic hydrophilic group excepting the polyoxyalkylene group can be thought of, but now silicone surfactants having a plyalcoholic hydroxyl group as a hydrophilic group are hardly known except that a polyglycerin denatured silicone disclosed in Japanese patent publication No. Sho 62-34039 and a sorbitan denatured silicone disclosed in Japanese patent laid-open No. Sho 57-209295 are known so as to exhibit the surface active action.
Further, silicone compounds denatured by a glyceryl group as a polyalcoholic hydroxyl group are known, as disclosed in Japanese patent laid-open Nos. Sho 62-195389, 64-16793 and 63-101388, but these compounds are surface modifiers making use of reactivity of the hydroxyl group for synthetic resins, and their surface active actions are unknown.
As described above, there is practically nothing at all of nonionic silicone surfactant having sufficient capability up to now.
In the meantime, conventionally, water-in-oil type emulsifying dermatotherapeutic external agents represented by water-in-oil type emulsifying cosmetic preparations have been widely used in virtue of their excellent properties such as good fitness to a skin due to a film formed on a skin surface, good cosmetic adhesiveness and the like.
However, on the contrary, the water-in-oil type emulsifying dermatotherapeutic external agents have drawbacks such as bad slip on applying, strong oiliness and stickiness feelings and the like. Hence, recently, silicone oils as an oil solution having less sticky or plain and smooth usage feelings and excellent water repellency have been mostly used, but it is difficult to emulsify the silicone oils and thus extremely difficult to obtain an emulsifying system having excellent stability.
Therefore, it has been desired to develop novel emulsifiers capable of stably emulsifying not only usual oil solutions but also silicone oils and giving good usage feeling when applying on a skin.